Stuttering / Idle problem...only in mornings

[weirdsong1]

For over a month now, my buddy 125 has had a very noticeable stuttering problem when I first start it up in the morning. Once it's had time to warm up, it's usually pretty good and runs without incident. 8 hours later when I bring it home from work, it doesn't have the same problem. Just mornings. However, recently, the problem has seemed to get worse. It has stalled at red lights (seemingly after having had plenty of time to warm up) and backfired a couple times. But it always fires right back up again, and seems to run fine once I give it enough gas.

I first noticed the problem when I picked up the scooter from it's last mystery problem. The mechanic weren't 100% sure what was causing my (then) power problem (cutting out at high speeds), but they replaced the coil and that has indeed solved that problem (and that was only 3 months after I had to replace the stator).

I'm hardly mechanically inclined, but I'm hoping I can solve this problem myself. This is my sole mode of transportation and I prefer not to have it in the shop for a week while they take their time with diagnostics. I thought the coil wires might be loose, or the spark plug, but no. It's had oil and oil filter changes (not that I suspected those things) in the past couple weeks. I would say the valves or carb, but when it was in the shop (just last month), they checked those things and said they were right.

I've also considered an oil/air mixture problem, so I adjusted the idle to make it run faster. When on the center stand it indeed idles faster and sounds pretty normal. However, when I get back on it, the idle gets considerably slower (although still running just fine once it's fully warmed up). This of course has me baffled.

Any thoughts would be greatly appreciated!

[C2]

I've got an appointment at SF Scooter Center for a tune up and 5200mi checkup this weekend. I've had similar issues - my scoot doesn't seem to like cold, damp mornings. I'll ask them and report back what I learn.

[Dooglas]

Assuming your air filter is clean, the other likely issues are a little gunk in your idle jet or a sticking auto choke.

[lovemysan]

Sounds like the automatic choke is sticking off. Or You might have a dirty carb , need a new carb or auto enrichment solenoid. The autochoke, or auto enrichment solenoind is called the auto bystarter set in the parts breakdown. It cost $62. A whole new carb is around $150. It could be wiring issue as well. The way it works is when cold the enricher opens the enrichment circuit. When you start the scooter voltage is sent to the enricher this is fed to a heating circuit which heats a small amount of wax that forces the plunger down closing the enrichment circuit. It's easy to test if your mechanically inclined. Remove the screw and gently work the "auto choke" out of the carb. Leave it connected to the wiring. Be careful as you can damage the plunger(yours sounds like it sticks full out all the time). I gently spin then rock it loose pulling straight out. You'll need a friend for this, put a finger over the autochoke hole and hold it there. With a free hand hold the autochoke up and observe. Now start the scooter and hold it at idle or close to it. At this point 12 volt power will be sent to the unit. In a minute or so you should see the enricher slowly extend. If it doesn't move you have no 12v power going to it or its defective. Now that said try this at your own risk don't forget your dealing with flammable liquid here. And always remember an Internet diagnosis is not always a correct one. Good luck.

[weirdsong1]

Thanks guys. Cleaned the idle (and main) jets and replaced the spark plug. I'm letting the bike warmup for 3 or so minutes before I ride it, and that (and maybe the new spark plug) has seemed to help a little. But, it's most likely just a bandaid or coincidence, because it's hard to not be convinced that it is indeed the autochoke. It is so clearly a warmup issue.

Thanks, lovemysan, for the excellent walkthrough. I hope to run that test for myself this weekend.

[michelle_7728]

You might try putting some Seafoam in your gas also. You will find lots of references to it here on the forum, though typically it is in reference to winterizing your scooter. I was reading the reviews on it last night and some are hilarious...though in a good way. http://www.amazon.com/Sea-Foam-SF-16-Mo ... B0002JN2EU

Adding an ounce to your gas may not cure your issue, but it's good maintenance anyhow, and fairly inexpensive since the can will last you a long time if used mainly for your scooter.

Good luck!

[PIStaker]

Not sure about how the seasonal change in FL, but I find that I have to adjust the idle with each change of season.
Has Spring sprung in FL, or is that not an issue?

[weirdsong1]

Got sufficiently annoyed enough that I took in to the shop. They essentially ran the test that lovemysan detailed. The autochoke was definitely not working properly, but they wanted to see it when the bike is cold, so when the part arrives I'll bring it back in for a proper diagnostic.

Now that I'm pretty sure of the problem, I'm just very patient with the bike when cold. I let it warm up for at least 2 minutes before riding, and try not to stop once I get going. After a few more minutes, I'm usually good for the rest of the ride no problems at all.

Although, I'm committed to letting the pros replace the autochoke, I'm wondering if this is the sort of project people here would do themselves. Never really assessed the difficulty.


On an unrelated note, these mechanics (we finally have a Genuine dealer/shop in town) strongly discourage the use of fuel additives, including SeaFoam, although they admitted that particular stuff has some benefits for people who don't drive their scooter often (unlike me). They also strongly recommended using high octane gas (I know I know), completely unprompted. I've now dealt with 4 shops with this bike, and 3 of them have (again, unprompted) strongly suggested high octane gas. These guys went further to tell me to get my gas from the marina where it's ethanol free.

[weirdsong1]

Not sure about how the seasonal change in FL, but I find that I have to adjust the idle with each change of season.
Has Spring sprung in FL, or is that not an issue?

On the subject of weather, when I first started experiencing a problem, I chalked it up to this since it more or less coincided with Spring (which simply means hotter and more humid in florida). But after about the 4th tank of gas and the same symptoms, I suspected more. To be honest, I'm not sure if weather has an effect on bikes in florida -- my experience says no. A question for the forum...is humidity (or hot temperature) a problem for scooters?

[sadtosell]

I just dropped an ounce of seafoam in the gas tank, rode the scooter for about 2 - 3 miles, some have suggested to leave in overnight. When I rode the scooter it would stall at every stop. Ran great full throtle. I need to sell it I hope this isn't a major for the next owner. It has less the 900 miles on it.

[Throwback7R]

it's easy to change the hardest part is getting to the 1 screw. I am pretty sure you do not even have to take the carb out to replace it .

[michelle_7728]

I just dropped an ounce of seafoam in the gas tank, rode the scooter for about 2 - 3 miles, some have suggested to leave in overnight. When I rode the scooter it would stall at every stop. Ran great full throtle. I need to sell it I hope this isn't a major for the next owner. It has less the 900 miles on it.

sadtosell - Regardless of what some mechanics say, the Seafoam bit is something that (if you do a search) a lot of people on the forum do to help with:
* winterizing their scooter
* if they just will not be riding their scooter often
* to help combat a small amount of condensation in your tank
* as an additive

You might check out Stormswift's post on Sun May 15, 2011 3:09 pm in this thread....it sounds similar to what you are describing:
viewtopic.php?t=18456&highlight=vapor+lock

However, Seafoam may or may not be cure for what ever your issue is. If it IS just gas related, it could be:
1. You got a bad tank of gas and it's going to have to run it's course (or maybe drain it out and fill with new???).
2. Have you overfilled it? (filled it up beyond that inner lip that you see a couple of inches down in the gas filler neck?)
3. Has it fallen over recently? Maybe it still has gas spilled in to an area that is causing issues (again, I'm obviously not a mechanic...)
4. Are you in an area of the country that is already very hot? Maybe you have vapor lock? You might want to remove your gas cap and verify it is vented, and if not drill a hole in it to do so--while it's not on the scooter, of course If you do searches of the forum and you will find LOTS of threads with reference to vapor lock. Here is one: viewtopic.php?t=22707&highlight=vapor+lock

With just 900 miles, is it still under the two year warranty? If so, absolutely take it to your dealer. I have owned 3 Buddys and none of them have had the issue you are describing (2,500 on one I sold, and 1,700 & 6,500 on a 2nd and 3rd, which I still have).

Here's another good thread to read about stalls: viewtopic.php?t=18438&highlight=vapor+lock

My latest mechanic has also recommended using premium, but there have been numerous threads (example: viewtopic.php?t=19664&highlight=premium++regular), that argue that point...even say it can be harmful after a while. I like my mechanic, but this is one area I've decided to differ with him, and have continued using regular anyhow.

If you don't find a cure in the threads above, and do searches that don't help you resolve your issue, please do start your own thread with more background on your scooter (also include whether it's a 50cc, a 125cc or a 170cc) so you can get input from people more mechanically inclined than me regarding your specific issue.

Good luck!

[sadtosell]

I turned the knob a bit and it worked better then i took it for a ride and was fine for a couple of stops then it began stalling again......people in cars aren't very kind to stalled scooters. Well, I had not turned it on since mid winter I have a felling its gunk.

[weirdsong1]

So it turns out it wasn't the auto-choke, but indeed a wicked case of vapor lock. Fuel got inside the line and drowned out the system. Never even occurred to me since symptoms were closely aligned with idle, lasted well over a month, and all my previous vapor lock experiences were mid-ride. Oh well.

Thanks, michelle, for the good summary and links. I've never been tempted to jump to the premium gas, but when mechanics just keep saying it...

[JHScoot]

i have those exact same morning symptoms

[weirdsong1]

This saga just won't end. The mechanic's " bad case of vapor lock" proved not to be the case. Problem never disappeared and had to wait another week to bring the bike back in. I suspect we'll end up back at auto-choke.

[BuddyRaton]

Not sure about how the seasonal change in FL, but I find that I have to adjust the idle with each change of season.
Has Spring sprung in FL, or is that not an issue?

What is this "Spring" of which you speak?

Summer started last week! 90s and rain

[TVB]

The solution that worked for my stuttering / idle in the morning problem was a course in public speaking.

[tortoise]

I suspect we'll end up back at auto-choke.

Make some test runs with the auto-choke connector unplugged. If there is a noticeable difference, might consider installing an enricher switch.

Another potential gremlin is a quirky CDI. Some go quirky hot and others cold . . example. Standard GY6 CDI and ignition coil replacements are relatively cheap . . performance units often only enhance your grief.

[weirdsong1]

Replacing the auto-choke seems to have solved the problem. Thanks so much guys for the suggestions.

BUT...I can't believe it, but after picking up the bike, it seems i've discovered a new problem. I should start by saying that I had them replace the belt and rollers along with the auto-choke. But, almost immediately after picking up the repaired scooter it started randomly losing throttle at higher speeds (50 mph+), and then would regain power quickly -- no more than once or twice a ride. The scooter also seems to surge at a stop, which suggests to me that the idle is set too high. However, this morning on the way to work, it lost throttle and didn't get it back -- rolled to stop and then the engine cut out. Let the bike sit for a few minutes, and started it back up again. Rode fine the rest of the way to work (I kept my mphs down).

I'm totally baffled. This is now 8 weeks of fighting issues. First, I replaced the ignition coil which seemed to immediately cause the auto-choke/vapor-lock problem, which in turn has now caused this new symptom.

Are these problems all related, or just coincidental? Bike has about 9000 miles.

[Tocsik]

The solution that worked for my stuttering / idle in the morning problem was a course in public speaking.

I was going to recommend speech therapy.